Plasma addressed micro-mirror display

ABSTRACT

A gas discharge addressed display comprising a matrix of micro-mechanical picture elements with optical properties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to display panels and concerns matrixaddressing of displays with micro-mechanical light modulators. Moreparticularly, the invention concerns matrix addressing of electrostaticforce actuated micro-mirror displays utilizing low pressure gasdischarge.

2. Discussion of the Prior Art

Flat panel displays comprise an array of picture elements that generateor modulate light to provide an image. To supply data to individualpicture elements an addressing structure is employed comprising row andcolumn electrodes and an electronic switch for each picture element.Currently thin film transistors are used as an electronic switch inliquid crystal flat panel displays and gas discharge is employed foraddressing in plasma displays. Gas discharge addressing also has beenproposed for liquid crystal and electro-luminescent displays.

U.S. Pat. No. 4,896,149 issued to Buzak et al., describes an addressingstructure using an ionizable gaseous medium to address data storageelements defined by overlapping areas of multiple column electrodes on afirst substrate and multiple channels on a second substrate. A layer ofdielectric material separates the first and second substrates. Each ofthe channels of the Buzak et al. structure includes a referenceelectrode and a row electrode. The reference electrode is set at groundpotential and the row electrode receives negative-going DC pulse signalsto selectively effect ionization of the gas contained within thechannels.

U.S. Pat. No. 5,519,520 issued to Stoller describes a matrix-type flatpanel display in which an AC plasma gas discharge system uses spatialmodulation to control the gray-scale of a liquid crystal layer. Theliquid crystal medium is one which is operable in an on-off (bi-level)mode where the total area of saturation is directly determined by thespatial area charged by the gas discharge contiguous or adjacentthereto. A charge storage surface, such as a dielectric layer between atransparent electrode array, the LC medium and the gas medium stores acharge which is caused to spread in proportion to the amplitude ofconjoint voltages at selected matrix cross-point. The charge spread areaestablishes a spatial or area size of the spot where the liquid crystalmaterial changes state thereby providing spatial gray level of lighttransmission at the selected matrix cross-points.

As will be discussed in greater detail in the paragraphs which follow,the present invention, which is clearly distinguishable from the priorart, is uniquely directed to matrix addressing for displays based onmicro-mechanical actuators with optical properties that modulate light.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a gas dischargeaddressed display panel with picture elements comprised ofmicro-mechanical light modulators. In one form of the invention thisobject is achieved by providing a plurality of first and secondaddressing electrodes and a plurality of picture elements on asubstrate. Each picture element comprises a micro-mechanical actuatorwith optical properties and an actuation electrode. Each actuationelectrode forms a capacitor with selected ones of first addressingelectrodes and forms an arc gap operating in a low pressure dischargegas with selected ones of second addressing electrodes.

Another object of the present invention is to provide an addressingstructure for a display panel with micro-mechanical picture elements.This object is achieved by providing a plurality of first and secondaddressing electrodes and a plurality of picture element electrodes on asubstrate. Wherein each picture element electrode forms a capacitor withselected ones of first addressing electrodes and forms an arc gapoperating in a low pressure discharge gas with selected ones of secondaddressing electrodes and provides a voltage potential to selected onesof micro-mechanical picture elements.

Another object of the present invention is to provide an electroniccircuit for addressing a micro-mechanical picture element. This objectis achieved by providing in series connected electronic circuitcomprising of a first addressing electrode, a capacitor, an arc gapoperating in a low pressure discharge gas and second addressingelectrode. Wherein the equivalent circuit operates as voltage controlledself terminating current switch and provides a voltage potential to amicro-mechanical picture element.

The foregoing as well as other objects of the invention will be achievedby the novel display addressing structures and methods illustrated inthe accompanying drawings and described in the specification thatfollows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one form of the display panel of thepresent invention.

FIG. 2 is an enlarged cross-sectional view taken along lines 2-2 of FIG.1.

FIG. 3 is an enlarged, fragmentary, cross-sectional view of the areadesignated in FIG. 2 as 3-3.

FIG. 4 is a perspective view partly broken away to show internalconstruction of a display panel that implements one form of addressingstructures of the invention and carries out one form of the addressingmethods of the present invention.

FIG. 5 is a schematic view of a flat panel display of the invention thatincludes a display panel and associated panel drive electronics.

FIG. 6 is a schematic view illustrating the various voltage waveformsthat are applied to the row and column electrodes of the invention foraddressing the display panel.

FIG. 7 is a perspective view, partly broken way to show internalconstruction, of an alternate form of the display panel of theinvention.

FIG. 8 a schematic view of an alternate form of flat panel display ofthe invention that includes the display panel and the panel driveelectronics of the display.

FIG. 9 is a schematic view illustrating the voltage waveforms that areapplied to the row and column electrodes for addressing the displaypanel illustrated in FIG. 7.

DESCRIPTION OF THE INVENTION

Referring to the drawings and particularly to FIGS. 1 through 3, thesedrawings illustrate the construction and optical functionality of adisplay panel having an optical waveguide and tilting micro-mirrors ofthe character found in the embodiments of the invention that will bedescribed in the paragraphs which follow. As best seen in FIG. 1, thedisplay panel, which is generally designated by the numeral 20, includesa rectangular shaped optical waveguide 21 that is wedge-shaped in crosssection. Waveguide 21 is preferably constructed from an opticallytransparent material, such as acrylic or glass and comprises parallelfirst and second end surfaces 26 and 27 that are joined by parallel sidesurfaces 28 and 29 (see FIG. 1). Waveguide 21 also includes a speciallyconfigured major upper surface 30 and an upwardly inclined lower surface31 (see also FIG. 2). A plurality of equally spaced-apart grooves 32 areformed on upper surface 30 and, as shown in FIG. 1, extend between sidesurfaces 28 and 29. An elongated light source 24 is installed proximatethe wide edge 26 of the waveguide 21 and a matrix of tiltingmicro-mirrors 33 is constructed on upper surface 30 of the waveguide inFIG. 2. Also in FIG. 2, one column of the tilting micro-mirrors isdesignated as 33 a, 33 b, 33 c, 33 d, 33 e and 33 f.

Referring next to FIG. 3 of the drawings, groove 32, which isrepresentative of all of the grooves formed on the upper surface 30 ofthe waveguide 21, comprises three flat facets 34, 35 and 36. Asillustrated in FIGS. 2 and 3, facets 34 are inclined downwardly at asteep angle of between 80 and 90 degrees with respect to the uppersurface 30. Second facets 35 are recessed from and are parallel to theupper surface 30 and facets 36 are upwardly inclined at angles ofbetween about 45 and about 60 degrees with respect to upper surface 30.

As further illustrated in FIG. 3, multi-layer film coatings are appliedto facets 35 and 36. The first layer 37 is a light-absorbing blackpolymer film deposited only on facets 36. The second layer 38, which canbe formed from a material such as an aluminum alloy, comprises aconductive specularly reflective mirror film that is deposited on facets35 and on light-absorbing layer 37. The third layer 39 comprises atransparent electrical insulator that is deposited only on the flathorizontal sections of conductive mirror film layer 38.

FIG. 3 also illustrates one of the tilting micro-mirrors 33 e of thegroup of tilting micro-mirrors 33. Each of the tilting micro-mirrorscomprises a thin aluminum alloy elastic film that is affixed to theupper surface 30 of the waveguide 21. In order to bend the micro-mirrorat the tilt axis 42 (see FIG. 3), the thickness of each of themicro-mirrors is reduced at the junction of the downwardly inclinedfacets 34 with the upper surface 30 of the waveguide 21. For absorbingexternal light, a thin black polymer film 41 is deposited on the uppersurface of each micro-mirror.

In the present form of the display panel, the tilting micro-mirrors 33operate by electrostatic attraction force and by the counter springforces generated by the elastic film. Electrically, each tiltingmicro-mirror 33 represents a capacitor plate that forms a variablecapacitor with the conductive mirror films 38. When a suitable voltage“V” is applied between the fixed conductive mirror films 38 and amicro-mirror 33, the micro-mirror tilts by electrostatic attractionforce and, when no voltage is applied, the micro-mirror is returned tothe flat position by the counter spring force of the elastic film. As analternate to the grooves, appropriately configured cavities can beformed on the upper surface 30 of the waveguide and the tiltingmicro-mirrors can be received within the cavities rather than within thegrooves.

As best seen in FIG. 2 of the drawings, light rays 43 entering from thewide edge 26 of the waveguide 21 are uniformly distributed in the lightpropagation direction of the X-axis by total internal reflections andexit the waveguide 21 from downwardly inclined facets 34. Depending onthe positions of the tilting micro-mirrors, light rays are absorbed, ordirected to the viewer.

When a tilting micro-mirror is in the flat position, such as micromirrors 33 c and 33 d (FIG. 2), light rays reflect from the lower lightreflecting surfaces of the micro-mirrors and mirror coatings 38 and aredirected to the viewer. When a selected micro-mirror is tilted down,such as micro-mirrors 33 a and 33 b, light rays reflect from the lowerlight reflecting surface of the micro-mirror and mirror coatings 38 andchange the angles towards the normal. After multiple reflections, lightrays lose their energy and the light is absorbed. Some light rays maychange their angles of reflection by reflecting from the micro-mirrorsand mirror coatings 38 and such light rays re-enter the light guide fromdownwardly inclined facets 34 and travel backwards to the direction ofthe light source. (See micro-mirrors 33 e and 33 f as shown in FIGS. 2and 3.) Light-absorbing layers 37 absorb light rays traveling backwards.

Depending on the display size and resolution, each picture element mayinclude several tilting micro-mirrors. Reducing the size of individualmicro-mirrors helps to reduce the required electrostatic actuationvoltages. Also, micro-mirrors for each picture element may be grouped tomodulate different levels of light when suitable voltage is appliedbetween the fixed electrodes 35 a and a selected group of micro-mirrors.This reduces the display addressing constraints. The display panel shownin FIG. 1 may be constructed on a separate substrate and combined with abacklight assembly. The present invention provides matrix addressingstructures and methods for a display panel system of this type.

FIG. 4 shows a display panel 50, which implements one form of addressingstructures of the invention, carrying out the addressing methods of thepresent invention. The display panel of the present invention typicallyincludes significantly large numbers of picture elements and associatedaddressing electrodes. However, for illustration purposes only, fourpicture elements and two pairs of row and column electrodes are shown inFIG. 4 as first and second addressing electrodes for display panel 50.

As illustrated in FIG. 4, display panel 50 includes two parallel firstand second substrates 51 and 52 that are constructed from an opticallytransparent material, such as acrylic or glass, and are spaced apart byspacers 53. In the present form of the invention, the space between thesubstrates 51 and 52 is substantially filled with a discharge gas suchas neon, argon, helium and xenon or any mixture thereof at a pressurebetween approximately 30 torr and approximately 500 torr. These gasesare used in plasma displays and many other electrical appliances and arecalled an ionazable gas or a discharge gas.

As shown in FIG. 4 of the drawings, substrate 51 is rectangular in shapeand includes parallel first and second end surfaces 54 and 55 that arejoined by parallel side surfaces 56 and 57. Substrate 51 also includes aspecially configured major upper surface 58 and a spaced apart lowersurface 59. Equally spaced-apart grooves 60 are formed on upper surface58 and extend between the side surfaces 56 and 57. Provided on therecessed facets that are disposed within grooves 60 are first addressingor row electrodes R1 and R2. Row electrodes R1 and R2 are preferablydeposited from nickel or aluminum and are insulated with thin layers ofdielectric films 61.

Four tilting micro-minors M1, M2, M3 and M4 and second addressing orcolumn electrodes C1 and C2, which are constructed from thin aluminumalloy elastic film, are affixed to the upper surface 58 of substrate 51.In the present form of the display panel of the invention, the tiltingmicro-mirrors M1, M2, M3 and M4 are movable between first and secondpositions and operate by electrostatic attraction force between thetilting micro-mirrors and the respective row electrodes R1 and R2 and bythe counter spring forces generated by the elastic film. Electrically,each tilting micro-mirror represents a capacitor plate and forms, alongwith the row electrodes, a variable capacitor. Four arc gaps G1, G2, G3and G4 are formed between the column electrodes and micro-mirrors. Toprevent crosstalk, it is desirable to have minimum stray capacitancebetween the micro-mirrors and column electrodes. Therefore, only aportion of the column electrodes is extended closer to themicro-mirrors. For typical applications, the length of the arc gaps mayrange from a few micrometers to several hundred micrometers. Aspreviously stated, the present invention uses low pressure gas dischargefor addressing the micro-mirrors.

In operation, a minimum breakdown voltage Vb is required to initiate aspark between the column electrodes and the micro-mirrors. The requiredminimum breakdown voltage Vb generally follows Paschen's law, whichstates that the minimum breakdown voltage of a gap is the product of thegas pressure and the gap length. This is a non-linear function and istypically written as Vb=f(p*d), where p is the pressure and d is the gapdistance. During operation, and to prevent arcing between columnelectrode C1 and micro-mirrors M2 or M4, the distance d1 between columnelectrode C1 and micro-mirrors M2 and M4 is made significantly largerthan the length of the arc gaps.

FIG. 5 illustrates a schematic diagram of a flat panel display 65 thatincludes display panel 50 and panel drive electronics. As depicted inFIG. 5, data processing and display scanning electronics block 62provides scanning signals to the row drivers 64 for sequentiallyselecting row electrodes of display panel 50 and provides synchronizeddata signals to column drivers 63. Block 62 also provides a synchronizedcontrol signal to the light source 67. Row drivers 64 and column drivers63 include shift registers and buffer amplifiers for driving theelectrodes of display panel 50. Typical buffer amplifiers includecomplimentary transistors and reverse biased protection diodes.

In FIG. 5, the tilting micro-mirrors of display panel 50, which formcapacitors with the respective portions of the row electrodes, areillustrated as capacitor plates M1, M2, M3 and M4. Also shown in FIG. 5are four arc gaps G1, G2, G3 and G4, each having a first terminalconnected to the respective column electrodes C1 and C2, and a secondterminal connected to the respective capacitor plates M1, M2, M3 and M4.

FIG. 6 illustrates the various voltage waveforms that are applied to therow and column electrodes for addressing display panel 50. Additionally,FIG. 6 illustrates the voltage waveforms for micro-mirrors M1 and M2that are generated as consequence of voltages applied to the column andthe row electrodes. In FIG. 6 one video field time interval is shownthat comprises reset, addressing and display periods. Initially, thecolumn electrodes are set to 0V potential and the row electrodes to −40Vpotential. Initially the capacitors formed by the micro-mirrors and therow electrodes are discharged so that the micro-mirrors M1 and M2 havethe same −40V potential as the row electrodes.

As previously discussed, a specific minimum gas breakdown voltage Vb isrequired across the arc gap to initiate arc. Each gas discharge also hasa specific extinguishing voltage Ve which is approximately 70% ofbreakdown voltage Vb. For this application assume that the breakdownvoltage Vb=100V and the extinguishing voltage Ve=70V.

During the time interval T1, which is 1 microsecond or less, a 40V pulseis applied to the column electrodes C1 and C2, and −80V is applied tothe row electrode R1. This generates 120V potential across the arc gapsG1 and G2 and initiates an arc at each arc gap. The initiated arcscharge the capacitors formed by the micro-mirrors M1 and M2 andrespective portions of the row electrode R1. The charges applied to themicro-mirrors M1 and M2 raise the voltage potential of the micro-mirrorsup to 50V. Consequently, the voltage potential drops below theextinguishing voltage Ve=70V across the arc gaps and the arcsextinguish. The equivalent circuits operate as a voltage controlledself-terminating current switch.

During the time interval T2, the voltage on the column electrodes C1 andC2 is set to 0V and the row electrode R1 is raised to 70V potential.This adds to the 50V charge applied to the micro-mirrors M1 and M2during the T1 time interval and generates 120V potential across the arcgaps G1 and G2, initiating an arc at each arc gap. The initiated arcsdischarge the capacitors formed by the micro-mirrors M1 and M2 andrespective portions of the row electrode R1. This reduces the voltagepotential across the arc gaps from 120V to 70V and arcs extinguish.

In FIG. 6, the last two waveforms illustrate the voltage potentialdifferences that generate electrostatic attraction force between themicro-mirrors M1 and M2 and the row electrode R1. During the timeinterval T2, the previously actuated micro-mirrors reset to the upperflat position by the counter spring force generated by the elasticfilms. For this reason the T2 time interval is held sufficiently long(>20 microseconds). The described operations for the time intervals T1and T2 apply to all micro-mirrors and row electrodes of the display.

As shown in FIG. 6, during the addressing period and the time intervalT3, 40V is applied to the column electrode C1, 0V to the columnelectrode C2 and −80V to the row electrode R1. This generates 120Vpotential across the arc gap G1 and 80V potential across the arc gap G2.As the required breakdown voltage is Vb=100V, arc initiates only at thearc gap G1 and the initiated arc charges the micro-mirror M1 by 50V.Micro-mirrors actuate by the electrostatic force generated between therow electrodes and the micro-mirrors that receive 50V charge. Followingthe time interval T3, the addressing of the micro-mirrors M3 and M4 isperformed by applying a −80V pulse to the row electrode R2 andcorresponding data to the column electrodes.

Referring to FIG. 7, an alternate form of display panel of the inventionis there shown and designated by the numeral 70. This alternateembodiment, which implements the addressing structures and carries outthe addressing methods of the present invention, is similar in somerespects to the embodiment shown in FIG. 4 of the drawings and likenumbers are used in FIG. 7 to identify like components.

Display panel 70 here includes two spaced apart, parallel substrates 51and 52 that are constructed from an optically transparent material, suchas acrylic or glass. In the display panel 70 the addressing structuresare built on the front cover substrate 52 and the micro-mirrors and thelower electrostatic actuation electrodes are built on the substrate 51.The substrate 51 is rectangular shaped and comprises parallel first andsecond end surfaces 54 and 55 that are joined by parallel side surfaces56 and 57. Substrate 51 also includes a specially configured major uppersurface 58 and spaced apart lower surface 59.

Equally spaced-apart grooves 60 are formed on upper surface 58 andextend between the side surfaces 56 and 57. Lower electrodes L1 and L2,are carried on the recessed facets that are disposed within grooves 60and are deposited from aluminum and insulated with thin transparentdielectric films 61. Four tilting micro-mirrors M1, M2, M3 and M4 andfirst and second micro-mirror drive electrodes E1 and E2, which areconstructed from thin aluminum film, are affixed to the upper surface 58of substrate 51. Electrode E1 is electrically connected to themicro-mirrors M1 and M2 and electrode E2 is electrically connected tomicro-mirrors M3 and M4. First addressing or row electrodes R1 and R2,which include a rectangle shaped capacitor plates P1, P2, P3 and P4, arecarried on the lower surface 73 of the substrate 52 and are depositedfrom aluminum. As shown in FIG. 7, capacitor plates P1, P2, P3 and P4are positioned above the respective micro-mirrors.

Row electrode R1 is electrically connected to capacitor plates P1 and P2while the row electrode R2 is electrically connected to capacitor platesP3 and P4. A thin transparent insulator 71 is spin coated on rowaddressing electrodes and capacitor plates P1, P2, P3 and P4. Fourrectangular shaped picture element electrodes A1, A2, A3 and A4, and twosecond addressing or column electrodes C1 and C2, which are constructedfrom aluminum film, are affixed to the lower surface of the insulator71. Portions of the column electrodes extend closer to the pictureelement electrodes forming the arc gaps G1, G2, G3 and G4. A thintransparent insulator film 72 is placed on the lower surface of pictureelement electrodes and the space between the insulator films 71 and 72is filled with a discharge gas at low pressure. This process, which issimilar to vacuum forming, deforms the insulator film 72 and createspockets for discharge gas at each arc gap between the picture elementelectrodes and the column electrodes.

In the display panel 70 picture elements represent a three electrodeelectrostatic actuators. Micro-mirrors M1, M2, M3 and M4 are movingelectrodes that are positioned between the respective upper pictureelement electrodes A1, A2, A3 and A4 and the lower electrodes L1 and L2.The electrostatic attraction force between the picture elementelectrodes and the micro-mirrors move the micro-mirrors to the firstupper flat position and the electrostatic attraction force between themicro-mirrors and the lower electrodes tilt the micro-mirrors in adownward direction toward a second position.

FIG. 8 illustrates a schematic diagram of a flat panel display 80 thatincludes the display panel 70 and the panel drive electronics of theinvention. The panel drive electronics here includes a block 74 forsequentially driving row electrodes R1 and R2 of the display panel 70, ablock 75 for providing synchronized data to the column electrodes C1 andC2, a block 76 for supplying voltage to the lower electrodes L1 and L2;and a block 77 for driving electrodes E1 and E2 of the display panel 70.In the display panel 70 each picture element represents three capacitorsconnected in series. The first capacitors are formed by the pictureelement electrodes A1, A2, A3 and A4 and the capacitor plates P1, P2, P3and P4 which are connected to the respective row electrodes R1 and R2.The second capacitors are formed by the picture element electrodes A1,A2, A3 and A4 and the micro-mirrors M1, M2, M3 and M4 which areconnected to respective drive electrodes E1 and E2. The micro-mirrorsM1, M2, M3 and M4, and the respective portions of the lower electrodesL1 and L2 form the third capacitors. Four arc gaps G1, G2, G3 and G4 areprovided in the display panel 70 with each having the first terminalconnected to the respective column electrodes C1 and C2, and a secondterminal connected to the respective picture element electrodes A1, A2,A3 and A4.

FIG. 9 illustrates the voltage waveforms that are applied to the row andcolumn electrodes for addressing the display panel 70. FIG. 9 alsoillustrates the voltage waveforms for A1 and A2 picture elementelectrodes that are generated as a consequence of the voltages appliedto the row electrode R1 and column electrodes C1 and C2. The last twowaveforms illustrated in FIG. 9 show electrostatic actuation voltagessupplied to the electrodes L1, L2, E1 and E2.

As previously discussed, the picture element electrodes form capacitorswith the row electrodes and the micro-mirrors. For the presentapplication assume that the capacitors formed with the picture elementelectrodes A1 and A2 and the row electrode R1 have 10 times greatervalue than the capacitors formed with the picture element electrodes A1and A2 and the micro-mirrors M1 and M2. The voltage values shown in FIG.9 account these 10 to 1 capacitive dividers.

As illustrated in FIG. 9, wherein two video field time intervals areshown, it can be seen that display panel 70 is capable of simultaneousaddressing and display operations. The display period of video field 0coincides with addressing period of video field 1 while the displayperiod of video field 1 coincides with addressing period of video field2.

Before a video field addressing period all picture element electrodesare reset to approximately the voltage potential of the row electrodes.Similarly, during each actuation period and before a video field displayperiod, all micro-mirrors are reset to their new positions.Additionally, during the actuation periods the light source is turnedoff and during the display periods the light source is turned on.

Initially the column electrodes are set to 0V potential and the rowelectrodes are set to −85V potential. For this application once againassume that the breakdown voltage of the discharge gas is Vb=100V andthe extinguishing voltage is Ve=70V.

During the time interval T1, which is 1 microsecond or less, 0V isapplied to the column electrodes C1 and C2 and about −140V is applied tothe row electrode R1. This generates a voltage potential across the arcgaps G1 and G2 that is greater than the breakdown voltage Vb=100V,thereby initiating an arc at each arc gap. The initiated arcs charge thepicture element electrodes A1 and A2 and raise the voltage potential ofthe picture element electrodes to about 70V.

Consequently, the voltage potential drops below the extinguishingvoltage Ve=70V across the arc gaps and the arcs extinguish. During thetime interval T2, the voltage on the row electrode R1 is raised to about87V potential. This raises and adds to the 70V charge applied to thepicture element electrodes during the T1 time interval and initiates anarc at arc gaps G1 and G2. The initiated arcs discharge the pictureelement electrodes A1 and A2. Consequently, the voltages drop across thearc gaps to about 70V and the arcs extinguish.

During the time interval T3, the voltage applied to the row electrode R1is reduced to about −85V, setting a voltage potential of approximately−85V on the picture element electrodes A1 and A2. It is to be understoodthat the previously described operations for the time intervals T1 andT2 apply to all row and picture element electrodes of the display panel70.

During the addressing period of video field 1 and time interval T4,about 10V is applied to the column electrode C1, 0V to the columnelectrode C2, and −95V to the row electrode R1. This generates a 105Vpotential across the arc gap G1 and a 95V potential across the arc gapG2. Because the required breakdown voltage is Vb=100V, arc is initiatedonly at arc gap G1. The initiated arc at arc gap G1 charges the pictureelement electrode A1 by about 35V. Following the time interval T3, a−95V pulse is applied to the row electrode R2 and corresponding data isapplied to the column electrodes.

During the reset and addressing periods, 0V is applied to electrodes E1and E2 and about 50V to electrodes L1 and L2. The 50V potential betweeneach tilted micro-mirror and the lower electrode supply a bias forcethat holds the micro-mirrors in tilted position. Similarly formicro-mirrors in the upper flat position, 50V or 85V potential betweeneach micro-mirror and respective picture element electrodes supply abias force that holds the micro-mirrors in the upper flat position.

Resetting the micro-mirrors to their new positions is a two stepprocess. First, the tilted micro-mirrors move to the upper flatposition, and then the micro-mirrors selectively tilt according to newaddressing.

During the actuation period and time interval T5, about 50V is appliedto the electrodes E1, E2, L1 and L2. These generate an electrostaticattraction force between each micro-mirror and respective pictureelement electrode. The generated forces move the previously tiltedmicro-mirrors to the upper flat position. Now all micro-mirrors are atthe upper flat position and closer to the picture element electrodes.During the time interval T6, the voltage potential of electrodes E1 andE2 is lowered to about −55V. This generates approximately 105V potentialbetween the lower electrode L1 and micro-mirrors M1 and M2, and 0Vbetween the picture element electrode A1 and the micro-mirror M1. Theelectrostatic force between micro-mirror M1 and lower electrode L1causes the micro-mirror M1 to tilt. The approximate 35V potentialbetween the micro-mirror M2 and the picture element electrode A2supplies a bias force between the micro-mirror M2 and the pictureelement electrode A2, holding the micro-mirror M2 at the upper flatposition.

While the embodiments of the present invention were described fortilting micro-mirrors, it is to be understood that there are severalother micro-mechanical light modulators for which the teachings of thepresent invention are applicable.

Having now described the invention in detail in accordance with therequirements of the patent statutes, those skilled in this art will haveno difficulty in making changes and modifications in the individualparts or their relative assembly in order to meet specific requirementor conditions. Such changes and modification may be made withoutdeparting from the scope and spirit of the invention, as set forth inthe following claims.

1. A display comprising: (a) a plurality of picture elements eachincluding a moving electrode for modulating light; (b) a plurality offirst and second addressing electrodes for selectively addressing saidplurality of picture elements; (c) a plurality of picture elementelectrodes, associated with the plurality of picture elements, forproviding a selective electrostatic force to said moving electrodes viaa gas discharge space formed between each of the plurality of pictureelement electrodes and the plurality of second addressing electrodes;(d) an ionizable gas in physical contact with said second addressingelectrodes and said picture element electrodes, and (e) an electroniccircuitry connected to said first and second addressing electrodes forselectively ionizing said ionizable gas and initiating an electricalconduction path in said gas discharge space between said secondaddressing electrodes and said picture element electrodes.
 2. Thedisplay according to claim 1 wherein said ionizable gas is physicallyisolated from said moving electrodes, said first addressing electrodesand portions of said picture element electrodes and said secondaddressing electrodes.
 3. The display according to claim 1 wherein saidfirst and second addressing electrodes, said moving electrodes and saidpicture element electrodes are formed from a light reflecting conductor.4. The display according to claim 1 wherein said moving electrodes areformed from an electricity conductor having a light absorbing firstsurface and light reflecting second surface.
 5. The display according toclaim 1 wherein said picture elements are arranged in a matrix form. 6.The display according to claim 1 wherein said picture elements arearranged in a matrix form and wherein each said first addressingelectrode is coupled with a row of said picture elements and each saidsecond addressing electrode is coupled with a column of said pictureelements.
 7. The display according to claim 1 wherein said firstaddressing electrodes are disposed orthogonal to said second addressingelectrodes.
 8. The display according to claim 1 in which said electroniccircuitry further connected to each of said moving electrodes forsupplying a first voltage potential to each said moving electrodes formoving each of said moving electrodes from a first position to a secondposition, supplying a second voltage potential for selectivelydisplacing each of the moving electrodes from said second position tosaid first position and supplying a third voltage potential to retaineach of the moving electrodes at one of said first and second positions.9. The display according to claim 1 further including means forsupplying an electrostatic force to each said moving electrodes formoving each of said moving electrodes from a first position to a secondposition, supplying said electrostatic force for selectively displacingeach of the moving electrodes from said second position to said firstposition and supplying a bias electrostatic force for retaining each ofthe moving electrodes at one of said first and second positions.
 10. Thedisplay according to claim 1 wherein said ionizable gas comprises atleast one of helium, neon, argon or xenon.
 11. The display according toclaim 1 wherein said ionizable gas has a pressure between 30 torr and500 torr.
 12. The display according to claim 1 further including a fixedelectrode and each said moving electrode is located between a selectedone of said picture element electrodes and said fixed electrode.
 13. Thedisplay according to claim 1 further including an optical waveguidehaving an upper surface, a plurality of light exit facets extendingdownwardly from said upper surface and a plurality of recessed facetsinterleaved with said light exit facets, and a fixed electrode formed onsaid recessed facets and connected to a first power supply, wherein saidmoving electrodes modulate the light exiting from said light exit facetsof said optical waveguide.
 14. The display according to claim 1 furtherincluding an optical waveguide having an upper surface, a plurality oflight exit facets extending downwardly from said upper surface and aplurality of recessed facets interleaved with said light exit facets,wherein said first addressing electrodes are formed on said recessedfacets, and wherein said moving electrodes modulate the light exitingfrom said light exit facets of said optical waveguide.
 15. The displayaccording to claim 1 further including an optical waveguide having anupper surface and a plurality of light exit facets extending downwardlyfrom said upper surface, wherein said moving electrodes modulate thelight exiting from said light exit facets of said optical waveguide. 16.The display according to claim 1 further including means for supplying abias electrostatic force to each of said moving electrodes to retainsaid moving electrodes at one of a first and a second position during avideo field addressing period.
 17. The display according to claim 1wherein said first addressing electrodes provide an electrostatic forceto said moving electrodes via said picture element electrodes.
 18. Thedisplay according to claim 1 wherein said electronic circuitry providesa first polarity voltage potential followed by an opposite polarityvoltage potential between said first and second addressing electrodesfor resetting the first polarity voltage potential of said pictureelement electrodes.
 19. The display according to claim 1 furtherincluding an electrical insulator layer formed on said first addressingelectrodes and wherein said plurality of picture element electrodes andsaid plurality of second addressing electrodes are formed on saidelectrical insulator layer.
 20. The display according to claim 1 furtherincluding an electrical insulator layer formed on said first addressingelectrodes and wherein said plurality of picture element electrodes areformed on said electrical insulator layer.
 21. The display according toclaim 1 further including a plurality of capacitor plates each connectedto a selected one of said first addressing electrodes.